Process of manufacturing spaced plate arc extinguishers



Sept. 16, 1952 R. E. FRINK ET AL PROCESS OF MANUFACTURING SPACED PLATE ARC EXTINGUISHERS Filed Feb. 25, 1949 9 10 Fig.l.

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INVENTORS Patented Sept. 16, 1952 PROCESS OF MANUFACTURING SPACED PLAT-E ARC EXTINGUISHERS Russell E. Frink andR-obert G. Dickinson, Pittsburgh, Pa., assignors to Westinghouse Electric Corporation, East-Pittsburgh, Pa., a corpora tion of Pennsylvania.

. Application February 23, 1949, Serial No. 77,793

This invention relates generally to circuit interrupters, and more particularly to an improved process of manufacturing spaced plate type of air break circuit in-terrupters.

Certain featuresof the invention are set forth and claimed in our d isiona'l application filed February 16, 1952, Serial No. 271,924, and as.- signed to the assignee of the instant application.

Ihe invention relates to air-type spaced plate circuit :interrupters, particularly of the slotted plate type, in which the est ablished ,arc is moved laterally into the aligned slots provided by the several plates, to the closed ends of said slots where thearcisextinguished. {Either a magnetic field maybe provided to force the are into the aligned slots to effect theerrtinction thereof at :itheclosed endsof the slots, or-a gasgblast or other are moving .means may be eu' ioyed. Reference may be had "to -S. Patent No. 199, which .issuedMay- Z5, 1e48, 1t oFltobertwill:Dickinson and Russell :Fr'ink, andwhich is assigned to the assignee of the present application. This patent discloses the particular constructional details :of :the "air break slotted plate type ol-circuit interfrupteriunder consideration a-ndalsodfificribes the theory l of arc interruption.

- The spaced plate typeof circuit interrupter referred .to in the aforesaid patent. is made from .anumber of ,fiatrectangular ceramic plates hav- 'ing V-shaped notc'hes or slots extending inwardly :from one :en-d'of the pla'tes. The; slots-ar e u rsymmetrical about the center lineof the plates and are alternately staggered in the assembling :operation has :set forth in the ,aforesaid patent. "I hese plates are stacked with spacers between the :edges, leaving went spaces between adjacent plates. .The ,plates are placed with the open ends of the .slots lined up, but with .the ofiset zstaggered from side tossideaso that when the .arc ,iisdriven upinto the slots ,it is restricted and lengthened, and even'tua11y' interrupted in the :manner described in the .,aforesaid patent.

The stack assemblyis ,cementedtogetherand lbaked toma'ke it, for all practicalpurposes, a single unit. The individual [platesare Va high fired ceramic, and for that reason, are not perfectly Straight. and true. ,They areialsoratherfrag ile. The spacers,.which areplaced between'these plates must have enough flexibilityto allowfor this. unevenness and vstillvforrn .a.,gas-tight .joint. They mustalso beabie taster-1 dhighv temperature from the arcand preferably-must be. free :from carbonization.

Our invention eliminates the; use of separate spacer strips which;havelbcenzmade from azhigh .2 Claims. (Cl. 154- 102) grade asbestos rope packing and placed at the edge of the plates. We eliminate the preparatory step of running the rope through rollers to make it oblong in cross-section and bring it down to size. We also make it unnecessary for the workman to paint the edges of the plates with cement, and to manually place the rope spacers in place on the cement.

It is a general object of our invention to improve the method of manufacture of the stack of plates so that considerable time will besaved and hence the cost of production greatly reduced.

It is ,a further object of our invention to proyide an improved method of manufacture of the interrupting plate assembly by the automatic disposition of a heavy-bodied cement between the ,platesso as to eliminate the use of separate spacer strips and speed up the manufacturing processes and givea uniform product.

Further objectsand advantages will readily bepome apparent uponreading the following specification talcen in conjunction with-the drawings, n which:

Figure l is a side .elevational view, partly in yer-ti al section of an air break spaced plate type of 'rcuit interrupter indicating the type of apparatus under consideration and in which an assembledstack of slotted spaced plates is utili ed;

wFig. Zis an enlarged plan iew of one of the individual plates utilisedin the circuit interrupter of F1 .1. showing alsothe two lengths of spacing 1 11a palet e? edges Qf thsrlat i is-a s e detai e -Iver rt y in t ca sect on a ve i iag m t c atin gone possible form; of apparatus used in our improved-process and shown at an intermediate ste c -disass m i pera n; an

Fig. ,4 is an .end.elevational yiew of the apz a 'a u sh w e i rla,

Referringto-the drawings, and more particularly to Fig. ;1 thereof, the reference numeral] generally designates contact structure which whenseparated,as shown, draws anew-fr, which, because of the loop. circuit provided, moves up- ,Wardly into engagement with the arc horns 3,15. The position of the are at this time-of operation is designated by the reference numeral 5. Suitable plate structure generally designated .by the reference. character- 5 is provided, which is composed of a plurality of spaced plates l (Fig.2), e ach.;of which; has an unsymmetrical-elongated slot 8 provided therein.

1Theseveral, plates are preferably. .ofa highfired insulating. ceramic and are spaeedapart by spacer strips 9 so that an exhaust passage it extends upwardly out of the are chute between adjacent plates 7. The are is forced by the energization of the blow-out coil ll up into the slots 8 in a manner described in the aforesaid patent, and arc extinction occurs at the upper closed ends of the slots 8, with the exhaust gases passing upwardly between the plates 1 and out of the interrupter through the exhaust passages l6.

Figs. 3 and 4 show one possible form of apparatus which may be utilized in our improved process to speed up the assembling operation, and at the same time insuring uniform width of the spacing strips 9 at the edges of'the plates 8. Referring to Figs. 3 and 4, it will be observed that we have provided a gun 12 having two nozzles 13, [4 which extrude cement in ribbon formalong the outside edges of the several plates 1. Insulating spacer strips I are employed to maintain the spacing to the desired width prior to the baking operations. It will be noted that the plates 1 are moved by a carriage structure It mounted on rollers ll, the latter riding on a platform It diagrammatically represented. At the opposite ends of travel of the carriage l6 are limit switches 19, 20, each of which serves to deenergize a solenoid 2i encircling an armature 22. The deenergization of the-solenoid 2| closes a valve structure generally designated by the reference numeral 23 associated with each nozzle [3, Hi.

More specifically, the valve structure 23 ineludes an apertured valve plate 24, biased toward the left, as shown in Fig. 3, by a tension spring 25. Consequently, energization of the solenoid 2| during the intermediate portion of travel of the carriage It serves to attract the armature 22 toward the right, as viewed in Fig. 3, to bring the aperture 26 of the plate 24 directly in line with the nozzle M to permit a ribbon of cement to pass downwardly out of the nozzle 14 and along the edge of the particular plate I, which is at that time on top of the assembly B. When the carriage I6 has moved to the opposite end of its travel, it opens the limit switch to thereby deenergize the solenoid 2! to permit the tension spring to close the valve structure 23, stopping the flow of cement out of the nozzle {4. d

A workman may then place another plate '1 upon the plate structure 6 accompanied by one or more spacers. l5, and upon movement of the carriage [6 toward the left, the limit switch 20 will reclose to again energize the solenoid 2| to open the valve structure 23 to thereby permit a a pair of ribbons of cement to flow along the opposite edges of the upper plate 1. Upon return of the carriage 16 to its extreme leftward position, as shown in Fig. 3, the limit switch [9 is again opened to deenergize the circuit through the solenoid 2|, thereby permitting the tension spring 25 to close the valve structure 23, halting any further flow of cement out of the nozzles l3, M. The cement may be placed under suitable pressure by any suitable means. In the particular form shown in Fig. 3, a piston 21 is employed biased downwardly into compressive relation with the cement 28 by means of a compression spring 29. d

The carriage I6 may be provided with side supports 30 and one or more end supports 3 I. These side and end supports '30, 3| permit a workman to readily place additional plates I in the desired position without any means required for positional adjustment. Before each additional plate 1 is placed in position, the spacer strips 15 are disposed at the opposite ends of the plates 1 to maintain the required distance between the plates 1 prior to the hardening of the cement 28 in the baking operations.

Referringto Fig. 4, it will be noted that the ribbons of cement 32 when hardened form the insulating elongated spacer strips 9, previously referred to which are disposed between the plates 1 along the outer edges thereof.

Any suitable cement may be employed in our improved process. Preferably, the cement should have two properties. It should be resilient so as to accommodate irregularities in the plate I which may not be exactly fiat. Also, the cement should be free from carbonization so that during operation of the interrupter the resulting high temperature caused by the arc will not carbonize and tend to decompose the cement spacing between the plates 7. Preferably, the cement should have a major portion of finely divided inorganic insulating substances, such as powdered asbestos, powdered glass fibers, silica fiour or mica fiour or crushed limestone, and a minor proportion of a hardenable binder, such as urea-formaldehyde resin, melamine formaldehyde resin or sodium silicate.

Thus, we do not confine our invention to any particular cement. Any cement of the general composition as above mentioned may be suitable. However, a particular cement which we deem particularly satisfactory, is a cement made by mixing ground asbestos with a sticking and bonding agent, such as urea-formaldehyde varnish, the latter containing considerable calcium carbonate pigment for body. The asbestos and varnish are mixed together in propertions that will give a heavy-bodied cement which will extrude easily, be sticky, and have suiii- Y cient body to hold its shape well. Satisfactory results were obtained with a mixture of two parts of asbestos to one part varnish by weight. This cement may be placed in the gun l2 and extruded from the nozzles l3, M in the appa ratus disclosed in Figs. 3 and 4. Preferably, the nozzles have a diameter somewhat larger than the plate spacing. The assembly fixture or carriage I6 is provided to bring about relative motion between the plates 1 and the nozzles l3, M. The nozzles I3, 14 will then lay a pair of ribbons of cement on each edge of each plat-e I. The insulating spacers 15 are placed at the ends and the next plate I placed upon the stack 6 so that two more ribbons of cement may be extruded on the new plate and the process repeated until the stack is built. When the stack 6 has set long enough for the cement to par-v tially set up, it is transferred to a baking fixture and baked. After the assembly '5 has been baked, the insulating spacers I5 may be removed since the cement is sufficiently hard at this stage of the operation to provide the sole spacing means between the several plates 1.

This method of providing a spacing means between the plates 1, cuts down the assembly time and eliminates the expense connected with the cementing and assembling of the spacer strips formerly used. The baked cement between the plates has been found to have good insulating characteristics, and a stack 6 of such plates 1 was tested on successive arc interruptions and found to be very satisfactory.

The foregoing description of our invention discloses a method of eliminating the spacer strips used before and provides a simple and inexpensive and fast method of assembling the plates 1 into an interrupting stack 6. Cost has been reduced and uniformity achieved. Furthermore, the time involved in assembling the plates has been greatly cut down, and the cement has been found to adhere well to the plates 1 and provide a desirable spacing means separating successive plates I the desired distance apart.

Although we have shown and described several methods of assembling the plate structure 6, it is to be clearly understood that these were merely for the purpose of illustration, and that changes and modifications may readily be made therein by those skilled in the art without departing from the spirit and scope of the appended claims.

We claim as our invention:

1. The method of manufacturing spaced stacked plate are extinguishers having venting passages between the plates comprising setting a rigid plate into position, extruding a single ribbon of cement along each of two opposite edges of one side only of the rigid plate, placing another rigid plate over the first said rigid plate directly on said ribbons of cement and spaced a substantial distance from the latter by the aforesaid ribbons of cement to form a venting passage therebetween, extruding a single ribbon of cement along each of two opposite edges of the upper side only of the second said rigid plate, repeating the aforesaid operations until ,the desired number of spaced rigid plates is utilized in the stack, and hardening the cement to form spacing means between the rigid plates of the stack.

2. The method of manufacturing spaced multiple plate type are chute stacks having venting passages between the plates comprising setting a rigid plate into position, extruding a single ribbon of cement in plastic condition along each of two opposite edges of one side only of the rigid plate, the ribbon of cement being extruded with a thickness at least as great as the distance the rigid plates are to be spaced apart, placing a spacer on the plate, placing a second rigid plate over the first said rigid plate a substantial distance from the latter as determined by the aforesaid two ribbons of cement and the spacer to form a venting passage therebetween, extruding a single ribbon of cement in plastic condition along each of two opposite edges of the upper side only of the second said rigid plate, the ribbon of cement being extruded with a thickness at least as great as the distance the rigid plates are to be spaced apart, placing a second spacer on the second said rigid plate, continuing operations in like manner until the desired number of spaced rigid plates is assembled in the stack, baking the cemented stack of rigid plates with the spacers in position until the cement has hardened, and finally removing the spacers so that the assembled rigid plates are spaced a substantial distance apart by the aforesaid ribbons of hardened cement to form venting passages between adjacent rigid plates.

RUSSELL E. FRINK. ROBERT C. DICKINSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 17,048 Tupper July 24, 1928 1,523,702 Moeller et al. Jan. 20, 1925 1,825,308 Dorogi et a1. Sept. 29, 1931 2,264,628 Engert et al. Dec. 2, 1941 2,304,718 Swart Dec. 8, 1942 2,395,077 Southwick Feb. 19, 1946 2,409,100 Brady et a1. Oct. 8, 1946 2,454,100 Slayter Nov. 16, 1948 

1. THE METHOD OF MANUFACTURING SPACED STACKED PLATE ARC EXTINGUISHERS HAVING VENTING PASSAGES BETWEEN THE PLATES COMPRISING SETTING A RIGID PLATE INTO POSITION, EXTRUDING A SINGLE RIBBON OF CEMENT ALONG EACH OF TWO OPPOSITE EDGES OF ONE SIDE ONLY OF THE RIGID PLATE, PLACING ANOTHER RIGID PLATER OVER THE FIRST SAID RIGID PLATE DIRECTLY ON SAID RIBBONS OF CEMENT AND SPACED A SUBSTANTIAL DISTANCE FROM THE LATTER BY THE AFORE SAID RIBBONS OF CEMENT TO FORM A VENTING PASSAGE THEREBETWEEN, EXTRUDING A SINGLE RIBBON OF CEMENT ALONG EACH OF TWO OPPOSITE EDGES OF THE UPPER SIDE ONLY OF THE SECOND SAID RIGID PLATE, REPEATING THE AFORESAID OPERATIONS UNTIL THE DESIRED NUMBER OF SPACED RIGID PLATES IS UTILIZED IN THE STACK, AND HARDENING THE CEMENT TO FORM SPACING MEANS BETWEEN THE RIGID PLATES OF THE STACK. 